Process and rolling mill for the manufacture of finished seamless tubes



July 7, 1925.

J. GASS EN PROCESS AND ROLLING MILL FOR THE MANUFACTURE OF FINISHED SEAMLESS TUBES Filed Feb. 13. 1922 2 Sheets-Sheet 1 July 7, 192 5. I J-. GASSEN PROCESS AND ROLLING MILL FOR THE MANUFACTURE OF FINISHED SEAMLESS TUBES I Filed Feb. 13 1922 I "X42 Sheets-Sheet 2 Patented J uly 7, 1925 UNITED STATES 1,545,249 PATENT OFFICE Jo'sEr GAsSEN, or nnssnLnonr-aa'rn; GERMANY.

PROCESS AND ROLLING MILL FOR THE MANUFACTURE OF FINISHED SEAMLESS TUBES.

Application filed February 13, 1922. Serial No. 535,998.

To all whom it may concern:

Be it known that I, J osnr GAssEN, a citizen of the Republic of Germany, and resident of Dusseldorf-Bath, Germany, have ing the body to be rolled in an axial direction is well known. The body to be rolled is hereby first sent through a narrowing part of the pass, for the preparation of the hole, and then through an enlarging part of the pass, for the formation of the hole. Hereby the pass is formed by a single pair 'of rolls,

which may be shapedand arran ed in difl'erent ways. It has also been trie to produce,

- in the same way, finished tubes from thickwalled hollow bodies. In the rolling of the round hollow bodies by means of the devices of the prior art there is the difiiculty that the body to be.

rolled, when passing through the rolls, is

subject to certain influences at the varioussucceeding points of the pass which cause an increase or decrease in the speed of the movement, which depend on the ratio of the circumferences of both of the rolls and of the body to be rolled. The consequence thereof is that distorting influences are exerted on the body to be rolled, during its travel, such as to produce a stress of the material,-'w hich renders the rolling of walled hollow bodies impossible.

The purpose of the present invention is to overcome the drawback and even to produce thin-walled hollow bodies or finished seamless tubes either directly from the solid or from thick-walled hollow bodies already produced in some other way. This is accomplished by a process in which the body to be rolled continuously receives-for the preparation of the hole as, and more particularly, for the finishing of the tube, which is most important in this connection-such a movement that the coacting circumferences, both of the rolls and of the body to be rolled, roll-off on each other perfectly equally without abnormally distorting the product to be rolled.

This process consists of two working opthindevices which by way of example are shownin'a rather diagrammatical way in the accompanying drawings, in which I Fig. 1, shows a side view of the rolls on one side;

Fig. 2, a plan, partly in section;

Fig. 3, a side view of the rolls on one side when arranged under different angles of transport;

Fig. 4, a side view new mill;

Fig. 5, a plan to Fig. 4;

Fig. 6, a side view of another modification of my new mill;

Fig. 7, a plan to Fig. 6.

Figs. 1 to 3 show by way of example how- I proceed in the operation of the above men-- tioned process to produce finished seamless tubes directly from a solid body. In this case, the narrowing part of the pass is formed by two cylindrical rolls and the enlarging part of the pass by two conical rolls. Both pairs of rolls are driveneither of a modification of my separately or jointly by means of suitable a, -c,-which are arranged at theangle of:

transport 20:. Here the material solel undergoes a change in its section in so ar as analmost oval section is formed and the hole is prepared. These rolls are closely followed by two conical rolls 6, d, which are arranged either at the angle of transport 20:, as shown in Fig. 1, or at another angle of transport 2a,, as shown in Fig. 3; these rolls effect the formation of the tube. Up to the centre point g, the rolls a, c act upon the body to be rolled advancing it uniformly in a tangential and an axial direction, whereby the rolling pressure gradually increases as.

the rolls rm with each other the angle 3 and thus a narrowing part of the pass. The

opening of the pass is effected by the arrangement of the conical rolls 7), d forming with the rolls a, c'the angle 6. As the rollsrolling-E of the circumferences belonging together is effected practically withoutany distortion. By using the mandrel f which, with regard to length and diameter adapts itself to the opening outlet'of the rolls 1), d, it is possible to reduce the thickness of the wall to any desired extent. In this case, the outlet rolls 1), cl work in combination with the mandrel f as a three-high rolling mill, working the tube, so to say, like a continuously advancing endless band.

The joint between the rolls a, 0 and 5, cl should, properly speaking, be at the narrowest part of the pass in the zone of the centre point 9. In this case, the ends of the cylindrical rolls would, however, become very sharp edged and possibly brealeout. For this reason, it will be preferable to glve the adjacent ends of the cylindrical rolls a slight conical shape, as'shown in Fig. 2' Owing to this slight deviation from the cylindrical shape of the rolls a, c, the circumferential velocity undergoes on this short crossing way, a slight deviation, which, although being contrary to the rule, is, however, practically of no consequence.

Fig. 1 shows both pairs of rollsarranged at the same angle of transport 20:, wheras Fig. 3 shows the possibility of different angles of transport.

The above example shows the entire reali- .zation of the invention, both as regards the performances of the preparation of the hole as of the finishing of the tube, whereas Figs. 4 to- 7 show other modifications of my new invention, by which the narrowing part of the pass is not formed bycylindrical rolls but by disc-rolls. enlarging part of the pass, which is effected by the conical rolls 5, d, forms part of. the

' present invention. As mentioned before, the

preparation of the hole is effected, in this .case, under the distorting influence of the disc-rolls, owing to the increasing or decreasing diameter of the rolls. Such distortion, however, is not detrimental, because of the sections worked upon of the body to be rolled are still fairly massive and can therefore offer sufficient resistance to the distorting efi'ects.

After this working'operation follows the finishing of the hole or the formation of the tube by means of the conical rolls. The body 6 to be rolled is first worked upon by the two disc-rolls a, 0 Fig. 5, revolving in opposite directions, and which are arranged in equal proportion below and above the center line of the'body to be rolled in order In this case, solely the to exert, in theknown way, to obtain the necessary transporting effect on the latter,

"The third example of how I can proceed in the operation of this rolling process is shown in Figs. 6 and 7. Also in'this instance, the narrowing part of the pass'is formed by disc-rolls, whereast-he enlarging direction," is obtained in the known way by passing the body to 'berolled above or below of the center line of the disc-rolls. Two conical rolls 1), ti, as per this invention, are arranged closely behind the before mentioned disc-rolls. The center lines of the conical rolls-cut each otherin'the center line of the body to be rolledsee Fig. 7at the angle of transport, 2a,, in order toproduce a transporting effect. mandrel f finished tubes are produced also in this case by the conical rollsb, d;

Instead of the disc-rolls shown in Figs. at to 7, rolls of another shape may as well be used in combination'with the conical rolls.

In all the cases mentioned above, twoaxes disposed in angular intersecting relation .and the line'of tangential contact of the rolls with the stock substantially continuous longitudinally of the stock so that the stock at all points of its contact With the forming rolls is moved by said rolls at a uniform angular velocity.

2. In a tube rolling mill, a bore forming mandrel, and two pairs of stock engaging rollers, one roller in each pair on'one side of the stock, and the rollers at each-side of With the aid of the rolls upon one side of the stock with their I the stock having their axes disposed in in tersecting relation whereby the stock is movedat all points of its contact with said rollers at a uniform angular velocity over and upon said mandrel.

3. In a tube rolling mill, a bore forming mandrel, and two pairs of stock engaging rollers, one roller in each pair on one side of the stock, and the rollers at each side of the stock'having their axes disposed in intersecting relation whereby the stock is moved at all points of its contact withsaid and upon said mandrel, said rollers at each side of the stock being relatively positioned rollers at a uniform angular velocity over 5 4. In a tube rolling mil ha bore forming" mandrel, and two pairs-of stock engaging rollers, one roller in ea(:hqpaiaon one side at all points of its 'contact'vvithjf said rollers at," a uniform angular velocity; over and upon said'mandrel, and the rollers'of one" pair at opposite sides 0'15 the stock having their axes relatively positioned in a difiej entiangular relation with respect 't-O-{the' anguIar relation of themes of the iotherr pair of rollers.

5'. In a tube rolling mill, rollers to engage one side of thestock having their a'xes disposed in intersecting relation, and the peripheral faces of said roll .rs having a substantially longitudinally continuous line of tangential contact upon the stock;

6. In a tube rolling mill, rollersto engage one side of the stock having their axesdisposed'in intersecting relation, one of said rollers being of cylindrical form and having, a recessed end and the other roller beingof conical j forinflwi th the smaller end thereof positioned in the recess of said cylindri al.

roller whereby the peripheral faces of said cylindrical and conical rollers have .a sub stantially continuous."longitudinally extend-- I ing line of. tangential contact upon the stock.

' 7. In a rolling mill for producin hollow bodies from solid blocks, the combination com-prising a pairof cylindrical roll s'inclined tov each other, and a. pair of conical roll's incIined'toLeach' Otheryeach of the eylindrical r011 having 'a' concave, face into, which the adjoining conical. roll projects.

8. In a rolling mill for producing hollow bodies froin solid blocks, the. combination comprising a pair of cylindrical rolls and a pair of conical rollscoacting withs'aidicylindrical rolls, said cylindrical rolls being inclined to each other and- -ea'ch having a concave face tapering into 'the shape ofja cone directed towards one of the conical jects.

J OSEF GASSEN. 

